I loved Groove. And I can say that openly without all the Microsoft haters jumping down my throat because it wasn't created by Microsoft. Ray Ozzie's company Groove Networks put this incredible collaboration solution together and Microsoft scooped it up when it scooped up Ozzie a few years back. However, unlike other software products that get shelved when gobbled by the big fish, Groove was valuable, and Microsoft saw that. A quick tweak and it was released with the Microsoft Office 2007 suite.
Note: I say a quick tweak because Groove is one of those applications that didn't get enough of an overhaul with the full set of Windows 2007 Servers that Microsoft released for Office 2007, which included Forms Server, Groove Servers, Project Server, Project Portfolio Server, PerformancePoint Server, Communications Server, and SharePoint for Search. These are all very different server types, some relying on SharePoint Services, and others, like Groove, being a product unto itself.
[ Read the InfoWorld Test Center's review of SharePoint Server 2007, and get an early look at SharePoint 2010. | Read J. Peter Bruzzese's two-part series: "Getting into the Groove: Part 1" and "Getting into the Groove: Part 2." ]
Now, when I say I loved Groove, let me be clearer: I loved the client side of the process. The Groove client was a simple interface that allowed me to work online with others and collaborate, work offline and make edits and such, and then sync with others when I got back online. Groove had little snap-ins for notes, document libraries that connect to file servers or SharePoint libraries, forums for discussion, and even a Chess app that lets you play chess against fellow workspace folks. It worked great.
The server side, however, was a challenge. Three different Groove server types (Groove Manager, Groove Relay, and Groove Data Bridge) complicated the setup of an in-house Groove environment.